Evidence of surfactant protein A and D expression decrement and their localizations in human prostate adenocarcinomas

Surfactant proteins (SP-A and SP-D) were originally described in the lung; however, they are also present in the prostate. Purpose of this study, therefore, was to determine how surfactant proteins are altered in prostate adenocarcinomas (PCa) and find out any connection exists between their expressions and their staining patterns, prostate-specific antigen (PSA) values, Gleason score, age, tumor volume and tumor, node, metastases (TNM) clinical stage.

Thirty-five tissue samples were obtained during radical prostatectomy. All specimens were classified to three groups based on the Gleason score <7, 7 and Gleason score >7. Surfactant proteins' expressions were tested by immunohistochemical and Western blotting methods.

Immunoreactivity was detected in the cytoplasm from both basal cells and secretory epithelial cells in malignant and non-malignant areas. About 80% of the malignant basal cells were characterized as either weak or strong while non-malignant epithelial cells demonstrated strong immunoreactivity for SP-A. Also malignant (81.8%) and non-malignant cells (90.6%) were characterized as either weak or strong for SP-D. Decrement of SP-A and SP-D immunostaining tended to associate with an increasing Gleason score (p > 0.05, p < 0.05), tumor volume (p < 0.05, p > 0.05) and age (p > 0.05, p > 0.05). There was a strong positive correlation between Gleason score and tumor volume (p < 0.01). Also, either none or weak SP-A and SP-D immunoreactivity was observed specimens with Gleason score 7 or higher. SP-A and SP-D reacted with 34 kDa (SP-A) and 43 kDa (SP-D) immunoreactive single bands were decreased in tumor tissues.

The development of prostate cancer may be related to decreased level of surfactant protein A and D.